In response to the challenges associated with the traditional synthesis process of hymenidin,such as complex reaction steps,low yields,high costs,and environmental concerns,the synthesis process has been significantly...In response to the challenges associated with the traditional synthesis process of hymenidin,such as complex reaction steps,low yields,high costs,and environmental concerns,the synthesis process has been significantly enhanced by optimizing reaction conditions,screening for efficient catalysts,and incorporating the concepts of green chemistry.The optimized process has significantly improved the synthesis efficiency and product quality of hymenidin,reduced production costs,and minimized environmental pollution,thereby providing robust support for its industrial production and broad application.展开更多
In mass spectrometry, fragments with a mass higher than the original molecular ion provide valuable insights into the molecular structure and can guide the assembly and disassembly processes for chemical synthesis. He...In mass spectrometry, fragments with a mass higher than the original molecular ion provide valuable insights into the molecular structure and can guide the assembly and disassembly processes for chemical synthesis. Here, we report such an example and following up by modifying the solvothermal reaction conditions (temperature and time) it is possible to isolate the high mass species in crystalline form. [Zn_(4)L_(4)Cl_(4)] (Zn_(4)L_(4), L = N-methylbenzimidazole-2-methanolate) has a boat-like Zn_(4)O_(4) core but electrospray ionization mass spectrometry (ESI-MS) of the solution of its crystals shows higher mass peaks of Zn_(5)L_(5), Zn_(5)L_(6) and Zn_(6)L_(6) species. Thus, both disassembly and reassembly are highly probable processes. Consequently, [Zn(HL)_(2)Cl_(2)] (Zn1, L = N-methylbenzimidazole-2-methanolate), [Zn_(4)L_(6)Cl_(2)] (Zn_(4)L_(6), L = N-methylbenzimidazole-2-methanolate) and [Zn_(6)L_(6)Cl_(4)(CH_(3)O)_(2)] (Zn_(6)L_(6), L = N-methylbenzimidazole-2-methanolate) were prepared. The results of multistage ESI-MS of their dissolved crystals led to a proposed mechanism of their formation in the gas phase as follows: [Zn_(3)L_(4)] through [ZnL] → [ZnL(HL)] → [Zn(HL)_(2)] → [Zn_(2)L] → [Zn_(2)L_(2)] → [Zn_(2)L_(3)]. The mechanism was derived in conjunction with Gibbs free energies calculated using DFT of the fragments observed in the ESI-MS of Zn_(4)L_(4), Zn_(4)L_(6) and Zn_(6)L_(6). This work reveals the complex of chemical reactions, involving fragmentation and unexpected combination, under mass spectrometry condition which allows one to synthesize the observed transients, leading to mechanism of formation by correlation of solid-state/solution structural information.展开更多
Graphdiyne(GDY)is a two-dimensional carbon allotrope with exceptional physical and chemical properties that is gaining increasing attention.However,its efficient and scalable synthesis remains a significant challenge....Graphdiyne(GDY)is a two-dimensional carbon allotrope with exceptional physical and chemical properties that is gaining increasing attention.However,its efficient and scalable synthesis remains a significant challenge.We present a microwave-assisted approach for its continuous,large-scale production which enables synthesis at a rate of 0.6 g/h,with a yield of up to 90%.The synthesized GDY nanosheets have an average diameter of 246 nm and a thickness of 4 nm.We used GDY as a stable coating for potassium(K)metal anodes(K@GDY),taking advantage of its unique molecular structure to provide favorable paths for K-ion transport.This modification significantly inhibited dendrite formation and improved the cycling stability of K metal batteries.Full-cells with perylene-3,4,9,10-tetracarboxylic dianhydride(PTCDA)cathodes showed the clear superiority of the K@GDY anodes over bare K anodes in terms of performance,stability,and cycle life.The K@GDY maintained a stable voltage plateau and gave an excellent capacity retention after 600 cycles with nearly 100%Coulombic efficiency.This work not only provides a scalable and efficient way for GDY synthesis but also opens new possibilities for its use in energy storage and other advanced technologies.展开更多
Recently published in Joule,Feng Liu and colleagues from Shanghai Jiaotong University reported a record-breaking 20.8%power conversion efficiency in organic solar cells(OSCs)with an interpenetrating fibril network act...Recently published in Joule,Feng Liu and colleagues from Shanghai Jiaotong University reported a record-breaking 20.8%power conversion efficiency in organic solar cells(OSCs)with an interpenetrating fibril network active layer morphology,featuring a bulk p-in structure and proper vertical segregation achieved through additive-assisted layer-by-layer deposition.This optimized hierarchical gradient fibrillar morphology and optical management synergistically facilitates exciton diffusion,reduces recombination losses,and enhances light capture capability.This approach not only offers a solution to achieving high-efficiency devices but also demonstrates the potential for commercial applications of OSCs.展开更多
Natural products,with their remarkable structural and biological diversity,have historically served as a vital bridge between chemistry,the life sciences,and medicine.They not only provide essential scaffolds for drug...Natural products,with their remarkable structural and biological diversity,have historically served as a vital bridge between chemistry,the life sciences,and medicine.They not only provide essential scaffolds for drug discovery but also inspire innovative strategies in drug development.The biomimetic synthesis of natural products employs principles from biomimicry,applying inspiration from biogenetic processes to design synthetic strategies that mimic biosynthetic processes.Biomimetic synthesis is a highly efficient approach in synthetic chemistry,as it addresses critical challenges in the synthesis of structurally complex natural products with significant biological and medicinal importance.It has gained widespread attention from researchers in chemistry,biology,pharmacy,and related fields,underscoring its interdisciplinary impact.In this perspective,we present recent advances and challenges in the biomimetic synthesis of natural products,along with the significance and prospects of this field,highlighting the transformative potential of biomimetic synthesis strategies for both chemical and biosynthetic approaches to natural product synthesis in the pursuit of novel therapeutic agents.展开更多
Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive st...Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive structure-directing agents(SDAs), pricey raw materials, and eco-unfriendly fluorine-containing additives. Here, we contributed a cost-effective and fluoride-free synthesis method for synthesizing high-quality MFI zeolite nanosheets through a Silicalite-1(Sil-1) seed suspension and urea cooperative strategy, only with inexpensive colloidal silica as the Si source. Our approach was effective for synthesizing both Sil-1 and aluminum-containing ZSM-5 nanosheets. By optimizing key synthesis parameters,including seed aging time, seed quantity, and urea concentration, we achieved precise control over the crystal face aspect ratio and b-axis thickness. We also revealed a non-classical oriented nanosheet growth mechanism, where Sil-1 seeds induced the formation of quasi-ordered precursor particles, and the(010)crystal planes of these particles facilitated urea adsorption, thereby promoting c-axis-oriented growth.The obtained ZSM-5 nanosheets exhibited exceptional catalytic performance in the benzene alkylation with ethanol, maintaining stability for over 500 h, which is 5 times longer than traditional ZSM-5 catalysts. Furthermore, large-scale production of ZSM-5 nanosheets was successfully carried out in a 3 L highpressure autoclave, yielding samples consistent with those from laboratory-scale synthesis. This work marks a significant step forward in the sustainable and efficient production of MFI nanosheets using inexpensive and environmentally friendly raw materials, offering the broad applicability in catalysis.展开更多
Neurons are highly polarized cells with axons reaching over a meter long in adult humans.To survive and maintain their proper function,neurons depend on specific mechanisms that regulate spatiotemporal signaling and m...Neurons are highly polarized cells with axons reaching over a meter long in adult humans.To survive and maintain their proper function,neurons depend on specific mechanisms that regulate spatiotemporal signaling and metabolic events,which need to be carried out at the right place,time,and intensity.Such mechanisms include axonal transport,local synthesis,and liquid-liquid phase separations.Alterations and malfunctions in these processes are correlated to neurodegenerative diseases such as amyotrophic lateral sclerosis(ALS).展开更多
Background Milk synthesis is an energy-intensive process influenced by oxygen availability.This study investigates how hypoxia affects milk synthesis in BMECs,focusing on key genes involved in lactation and energy met...Background Milk synthesis is an energy-intensive process influenced by oxygen availability.This study investigates how hypoxia affects milk synthesis in BMECs,focusing on key genes involved in lactation and energy metabolism.Methods BMECs were cultured in a normoxic environment and then transferred to a hypoxia chamber with 1%O2 for specified durations.The study evaluated cellular responses through various molecular experiments and RNA sequencing.Small interfering RNA was employed to knock down HIF-1αto investigate whether the lactation-related phenotype alteration depends on HIF-1α.Results Hypoxia disrupted milk protein production by reducing mTOR/P70S6K/4EBP1 signaling and downregulating genes critical for amino acid transport and protein synthesis.Triglyceride synthesis increased due to enhanced fatty acid uptake and the upregulation of regulatory proteins,including FASN and PPARγ.Although glucose uptake was elevated under hypoxia,key enzymes for lactose synthesis were downregulated,suggesting a redirection of glucose toward energy production.Mitochondrial function was impaired under hypoxia,with reduced gene expression in TCA cycle,ETC,cytosol-mitochondrial transport,decreased ATP levels,increased ROS levels,and structural alterations.Additionally,lipid synthesis and glucose uptake depend on HIF-1α,while milk protein synthesis alterations occurred independently of HIF-1α.Conclusions Hypoxia alters milk synthesis in BMECs by disrupting milk protein synthesis,enhancing lipid metabolism,and impairing energy production.These findings provide valuable insights into the molecular mechanisms underlying the effect of oxygen deprivation on lactation efficiency,offering potential targets for mitigating hypoxic stress in the mammary glands of dairy animals.展开更多
Urbanization and industrialization have escalated water pollution,threatening ecosystems and human health.Water pollution not only degrades water quality but also poses long-term risks to human health through the food...Urbanization and industrialization have escalated water pollution,threatening ecosystems and human health.Water pollution not only degrades water quality but also poses long-term risks to human health through the food chain.The development of efficient wastewater detection and treatment methods is essential for mitigating this environmental hazard.Carbon dots(CDs),as emerging carbon-based nanomaterials,exhibit properties such as biocompatibility,photoluminescence(PL),water solubility,and strong adsorption,positioning them as promising candidates for environmental monitoring and management.Particularly in wastewater treatment,their optical and electron transfer properties make them ideal for pollutant detection and removal.Despite their potential,comprehensive reviews on CDs'role in wastewater treatment are scarce,often lacking detailed insights into their synthesis,PL mechanisms,and practical applications.This review systematically addresses the synthesis,PL mechanisms,and wastewater treatment applications of CDs,aiming to bridge existing research gaps.It begins with an overview of CDs structure and classification,essential for grasping their properties and uses.The paper then explores the pivotal PL mechanisms of CDs,crucial for their sensing capabilities.Next,comprehensive synthesis strategies are presented,encompassing both top-down and bottom-up strategies such as arc discharge,chemical oxidation,and hydrothermal/solvothermal synthesis.The diversity of these methods highlights the potential for tailored CDs production to suit specific environmental applications.Furthermore,the review systematically discusses the applications of CDs in wastewater treatment,including sensing,inorganic removal,and organic degradation.Finally,it delves into the research prospects and challenges of CDs,proposing future directions to enhance their role in wastewater treatment.展开更多
Constructing a framework carrier to stabilize protein conformation,induce high embedding efficiency,and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes.Hydrogen-bonded...Constructing a framework carrier to stabilize protein conformation,induce high embedding efficiency,and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes.Hydrogen-bonded organic frameworks(HOFs)have promising application potential for embedding enzymes.In fact,no metal involvement is required,and HOFs exhibit superior biocompatibility,and free access to substrates in mesoporous channels.Herein,a facile in situ growth approach was proposed for the self-assembly of alcohol dehydrogenase encapsulated in HOF.The micron-scale bio-catalytic composite was rapidly synthesized under mild conditions(aqueous phase and ambient temperature)with a controllable embedding rate.The high crystallinity and periodic arrangement channels of HOF were preserved at a high enzyme encapsulation efficiency of 59%.This bio-composite improved the tolerance of the enzyme to the acid-base environment and retained 81%of its initial activity after five cycles of batch hydrogenation involving NADH coenzyme.Based on this controllably synthesized bio-catalytic material and a common lipase,we further developed a two-stage cascade microchemical system and achieved the continuous production of chiral hydroxybutyric acid(R-3-HBA).展开更多
In general,the rapid growth of α-Fe clusters is a challenge in high Fe-content Fe-based amorphous alloys,negatively affecting their physical properties.Herein,we introduce an efficient and rapid post-treatment techni...In general,the rapid growth of α-Fe clusters is a challenge in high Fe-content Fe-based amorphous alloys,negatively affecting their physical properties.Herein,we introduce an efficient and rapid post-treatment technique known as ultrasonic vibration rapid processing(UVRP),which enables the formation of high-density strong magnetic α-Fe clusters,thereby enhancing the soft magnetic properties of Fe_(78)Si(13)B_(9) amorphous alloy ribbon.展开更多
2-substituted-1-amino-o-carboranes 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10)(R=CH_(3),1a;R=Ph,1b)were synthesized and the reactions of these compounds with the yttrium dialkyl complex[Y(L)(CH_(2)SiMe3)_(2)](L=[2-(2,5-Me_(2)C_(...2-substituted-1-amino-o-carboranes 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10)(R=CH_(3),1a;R=Ph,1b)were synthesized and the reactions of these compounds with the yttrium dialkyl complex[Y(L)(CH_(2)SiMe3)_(2)](L=[2-(2,5-Me_(2)C_(4)H_(2)N)C_(6)H4NC(Ph)=NDipp]-,Dipp=2,6-iPr_(2)C_(6)H_(3))were investigated.The 1H NMR spectroscopy indicate that the reaction of ytrrium dialkyl complex with one equivalent of 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10) produce the mixture of ytrrium alkyl-amido complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))(CH_(2)SiMe3)](R=CH_(3),2a;R=Ph,2b)and bis(amido)complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))_(2)](R=CH_(3),3a;R=Ph,3b).The yttrium bridging imido complex[Y(L)(2-CH_(3)-1-N-o-C_(2)B_(10)H_(10))]_(2)(4a)was obtained by heating the mixture at 55℃for 12 h.Complex 3a was isolated and characterized by treating the yttrium dialkyl complex with two equivalents of 1a.The structures of complexes 3a and 4a were verified by single-crystal Xray diffraction.CCDC:2424136,3a;2424137,4a.展开更多
Sunscreen agents derived from plants have been regarded as promising alternatives to artificial compounds.In this work,carbon dots(CDs)were prepared from carrot juice via a continuous microflowbased approach,where the...Sunscreen agents derived from plants have been regarded as promising alternatives to artificial compounds.In this work,carbon dots(CDs)were prepared from carrot juice via a continuous microflowbased approach,where the influence of process parameters was studied and optimized.Complimentary characterization revealed the CDs not only have small size,narrow size distribution,and good water solubility,but also have abundant functional groups as well as excellent UV absorption performance.Relying on these properties,the CDs were used as UV absorbers,suggesting they have strong long-term UV absorption ability over a broad pH range.The UV-absorption properties of the CDs were confirmed by incorporating the CDs in polyvinyl alcohol(PVA)to get C-CDs@PVA films of different thickness,in which significantly enhanced UV absorption performance was observed.Besides,the sun protection performance is also related to the film thickness.Afterwards,the practical application of the CDs was evaluated by adding them in a typical skin cream.With the addition of the CDs,the cream has drastically reduced UV transmittance in both UVA and UVB regions,and exhibits better UV absorption performance than commercial sunscreen agents.The CDs also demonstrated low cytotoxicity and high DPPH radical scavenging activity,making them promising as green sunscreen absorbers.This work is expected to provide a guidance for the development of green and effective natural sunscreen agents via microflowbased method.展开更多
Fischer-Tropsch synthesis(FTS)and hydroformylation are pivotal chemical processes for converting syngas and olefins into valuable hydrocarbons and chemicals.Recent advancements in catalyst design,reaction mechanisms,a...Fischer-Tropsch synthesis(FTS)and hydroformylation are pivotal chemical processes for converting syngas and olefins into valuable hydrocarbons and chemicals.Recent advancements in catalyst design,reaction mechanisms,and process optimization have significantly improved the efficiency,selectivity,and sustainability of these processes.This Account introduces the relevant research activities in the Research Center for Catalysis in Syngas Conversion and Fine Chemicals(DNL0805)of Dalian Institute of Chemical Physics(DICP),Chinese Academy of Sciences.The reactions of interests include FTS,heterogeneous hydroformylation of olefins,alcohol dehydration and oxidation,andα-olefin polymerization,with the emphasis on developing innovative catalysts and processes to address the challenges of traditional processes.Exemplified by the discovery of robust Co-Co_(2)C/AC for FTS and Rh_(1)/POPs-PPh_(3) for heterogeneous hydroformylation of olefins,it demonstrates how lab-scale fundamental understandings on the active sites of catalysts leads to pilot-plant scale-up and finally commercial technologies.Perspectives on the challenges and directions for future developments in these exciting fields are provided.展开更多
Continuous research on Cephalotaxus plants has ultimately led to the US food and drug administration (FDA) ap-provalof homoharringtonine in 2012 for the treatment of chronic myeloid leukemia. Additionally, another imp...Continuous research on Cephalotaxus plants has ultimately led to the US food and drug administration (FDA) ap-provalof homoharringtonine in 2012 for the treatment of chronic myeloid leukemia. Additionally, another important class of natural products from Cephalotaxus plants is cephalotane diterpenoids. Since the discovery of the first member, harring-tonolide,in 1978, cephalotane diterpenoids have garnered significant attention from the scientific community due to their re-markableanti-cancer activity. The unique structural features of cephalotane diterpenoids, a 7/6/5/6-fused tetracyclic carbon skeleton and a bridged lactone, make them ideal targets for synthetic chemists. Successfully synthesizing these complex diterpenoids is of great importance for the discovery and development of anti-tumor drugs. To date, ten research groups have completed the total synthesis of 24 cephalotane diterpenoids. The latest progress in the total synthesis of cephalotane diterpe-noidsis reviewed, showcasing the importance of these innovative synthetic strategies in the efficient synthesis of complex natural products and their potential significance in advancing the field of drug discovery.展开更多
In order to improve the energy output consistency of 3, 3’-diamino-4, 4’-azoxyfurazan(DAAF) in the new insensitive booster and the safety and efficiency in the preparation process, a continuous preparation system of...In order to improve the energy output consistency of 3, 3’-diamino-4, 4’-azoxyfurazan(DAAF) in the new insensitive booster and the safety and efficiency in the preparation process, a continuous preparation system of DAAF from synthesis to spherical coating was designed and established in this paper, which combined ultrasonic micromixing reaction with microdroplet globular template. In the rapid micromixing stage, the microfluidic mixing technology with ultrasonic was used to synergistically strengthen the uniform and rapid mass transfer mixing reaction between raw materials to ensure the uniformity of DAAF particle nucleation-growth, and to prepare high-quality DAAF crystals with uniform structure and morphology and concentrated particle size distribution. In the microdroplet globular template stage, the microfluidic droplet technology was used to form a droplet globular template with uniform size under the shear action of the continuous phase of the dispersed phase solution containing DAAF particles and binder. The size of the droplet template was controlled by adjusting the flow rate ratio between the continuous phase and the dispersed phase. In the droplet globular template, with the diffusion of the solvent in the dispersed phase droplets, the binder precipitates to coat the DAAF into a ball, forming a DAAF microsphere with high sphericity, narrow particle size distribution and good monodispersity. The problem of discontinuity and DAAF particle suspension in the process was solved, and the coating theory under this process was studied. DAAF was coated with different binder formulations of fluororubber(F2604), nitrocellulose(NC) and NC/glycidyl azide polymer(GAP), and the process verification and evaluation of the system were carried out. The balling effects of large, medium and small droplet templates under different binder formulations were studied. The scanning electron microscope(SEM) results show that the three droplet templates under the three binder formulations exhibit good balling effect and narrow particle size distribution. The DAAF microspheres were characterized by powder X-ray diffraction(XRD), differential scanning calorimetry(DSC), thermo-gravimetric(TG) and sensitivity analyzer. The results showed that the crystal structure of DAAF did not change during the process, and the prepared DAAF microspheres had lower decomposition temperature and lower mechanical sensitivity than raw DAAF. The results of detonation parameters show that the coating of DAAF by using the above three binder formulations will not greatly reduce the energy output of DAAF, and has comparable detonation performance to raw DAAF. This study proves an efficient and safe continuous system from synthesis to spherical coating modification of explosives, which provides a new way for the continuous, safe and efficient preparation of spherical explosives.展开更多
Currently,the carbothermal reduction-nitridation(CRN)process is the predominant method for preparing aluminum nitride(AlN)powder.Although AlN powder prepared by CRN process exhibits high purity and excellent sintering...Currently,the carbothermal reduction-nitridation(CRN)process is the predominant method for preparing aluminum nitride(AlN)powder.Although AlN powder prepared by CRN process exhibits high purity and excellent sintering activity,it also presents challenges such as the necessity for high reaction temperatures and difficulties in achieving uniform mixing of its raw materials.This study presents a comprehensive investigation into preparation process of AlN nanopowders using a combination of hydrothermal synthesis and CRN.In the hydrothermal reaction,a homogeneous composite precursor consisting of carbon and boehmite(γ-AlOOH)is synthesized at 200℃using aluminum nitrate as the aluminum source,sucrose as the carbon source,and urea as the precipitant.During the hydrothermal process,the precursor develops a core-shell structure,with boehmite tightly coated with carbon(γ-AlOOH@C)due to electrostatic attraction.Compared with conventional precursor,the hydrothermal hybrid offers many advantages,such as ultrafine particles,uniform particle size distribution,good dispersion,high reactivity,and environmental friendliness.The carbon shell enhances thermodynamic stability of γ-Al_(2)O_(3) compared to the corundum phase(α-Al_(2)O_(3))by preventing the loss of the surface area in alumina.This stability enables γ-Al_(2)O_(3) to maintain high reactivity during CRN process,which initiates at 1300℃,and concludes at 1400℃.The underlying mechanisms are substantiated through experiments and thermodynamic calculations.This research provides a robust theoretical and experimental foundation for the hydrothermal combined carbothermal preparation of non-oxide ceramic nanopowders.展开更多
A strategy for the green synthesis of heterocyclicβ-ketosulfides via nucleophilic substitution ofα-halogenated ketone with het-eroaryl thiols in water media is presented.Compared with the available literature report...A strategy for the green synthesis of heterocyclicβ-ketosulfides via nucleophilic substitution ofα-halogenated ketone with het-eroaryl thiols in water media is presented.Compared with the available literature reports,this new method had the advantages of base-free,additives-free,simple operation,mild condition,greenness,high efficiency,tolerance of a broad scope of substrates.Furth-more,the reaction could easily be scaled up in gram scale and the products also could easily transformed to other useful organic compounds.Mechanism investigation indicated that the tautomerism of pyrimidine-2-thiol to pyrimidine-2(1H)-thione and the hy-drogen bonds played important roles in the reaction.展开更多
The rapid integration of Internet of Things(IoT)technologies is reshaping the global energy landscape by deploying smart meters that enable high-resolution consumption monitoring,two-way communication,and advanced met...The rapid integration of Internet of Things(IoT)technologies is reshaping the global energy landscape by deploying smart meters that enable high-resolution consumption monitoring,two-way communication,and advanced metering infrastructure services.However,this digital transformation also exposes power system to evolving threats,ranging from cyber intrusions and electricity theft to device malfunctions,and the unpredictable nature of these anomalies,coupled with the scarcity of labeled fault data,makes realtime detection exceptionally challenging.To address these difficulties,a real-time decision support framework is presented for smart meter anomality detection that leverages rolling time windows and two self-supervised contrastive learning modules.The first module synthesizes diverse negative samples to overcome the lack of labeled anomalies,while the second captures intrinsic temporal patterns for enhanced contextual discrimination.The end-to-end framework continuously updates its model with rolling updated meter data to deliver timely identification of emerging abnormal behaviors in evolving grids.Extensive evaluations on eight publicly available smart meter datasets over seven diverse abnormal patterns testing demonstrate the effectiveness of the proposed full framework,achieving average recall and F1 score of more than 0.85.展开更多
The newly emerging neural radiance fields(NeRF)methods can implicitly fulfill three-dimensional(3D)reconstruction via training a neural network to render novel-view images of a given scene with given posed images.The ...The newly emerging neural radiance fields(NeRF)methods can implicitly fulfill three-dimensional(3D)reconstruction via training a neural network to render novel-view images of a given scene with given posed images.The Instant Neural Graphics Primitives(Instant-NGP)method further improves the position encoding of NeRF.It obtains state-of-the-art efficiency.However,only a local pixel-wised loss is considered when training the Instant-NGP while overlooking the nonlocal structural information between pixels.Despite a good quantitative result,it leads to a poor visual effect,especially the completeness.Inspired by the stochastic structural similarity(S3IM)method that exploits nonlocal structural information of groups of pixels,this paper proposes a new method to improve the completeness of fast novel view synthesis.The proposed method first extends the thread-wised processing of the Instant-NGP to the processing in a customthread block(i.e.,a group of threads).Then,the relative dimensionless global error in synthesis,i.e.,Erreur Relative Globale Adimensionnelle de Synthese(ERGAS),of a group of pixels corresponding to a group of threads is computed and incorporated into the loss function.Extensive experiments validate the proposed method.It can obtain better quantitative results than the original Instant-NGP with fewer iteration steps.PSNR is increased by 1%.Amazing qualitative results are obtained,especially for delicate structures and details such as lines and continuous structures.With the dramatic improvements in the visual effects,our method can boost the practicability of implicit 3D reconstruction in applications such as self-driving and augmented reality.展开更多
文摘In response to the challenges associated with the traditional synthesis process of hymenidin,such as complex reaction steps,low yields,high costs,and environmental concerns,the synthesis process has been significantly enhanced by optimizing reaction conditions,screening for efficient catalysts,and incorporating the concepts of green chemistry.The optimized process has significantly improved the synthesis efficiency and product quality of hymenidin,reduced production costs,and minimized environmental pollution,thereby providing robust support for its industrial production and broad application.
基金supported by the BAGUI Talent Program in Guangxi Province(No.2019AC26001),and the National Natural Science Foundation of China(No.22171075,U23A2080).
文摘In mass spectrometry, fragments with a mass higher than the original molecular ion provide valuable insights into the molecular structure and can guide the assembly and disassembly processes for chemical synthesis. Here, we report such an example and following up by modifying the solvothermal reaction conditions (temperature and time) it is possible to isolate the high mass species in crystalline form. [Zn_(4)L_(4)Cl_(4)] (Zn_(4)L_(4), L = N-methylbenzimidazole-2-methanolate) has a boat-like Zn_(4)O_(4) core but electrospray ionization mass spectrometry (ESI-MS) of the solution of its crystals shows higher mass peaks of Zn_(5)L_(5), Zn_(5)L_(6) and Zn_(6)L_(6) species. Thus, both disassembly and reassembly are highly probable processes. Consequently, [Zn(HL)_(2)Cl_(2)] (Zn1, L = N-methylbenzimidazole-2-methanolate), [Zn_(4)L_(6)Cl_(2)] (Zn_(4)L_(6), L = N-methylbenzimidazole-2-methanolate) and [Zn_(6)L_(6)Cl_(4)(CH_(3)O)_(2)] (Zn_(6)L_(6), L = N-methylbenzimidazole-2-methanolate) were prepared. The results of multistage ESI-MS of their dissolved crystals led to a proposed mechanism of their formation in the gas phase as follows: [Zn_(3)L_(4)] through [ZnL] → [ZnL(HL)] → [Zn(HL)_(2)] → [Zn_(2)L] → [Zn_(2)L_(2)] → [Zn_(2)L_(3)]. The mechanism was derived in conjunction with Gibbs free energies calculated using DFT of the fragments observed in the ESI-MS of Zn_(4)L_(4), Zn_(4)L_(6) and Zn_(6)L_(6). This work reveals the complex of chemical reactions, involving fragmentation and unexpected combination, under mass spectrometry condition which allows one to synthesize the observed transients, leading to mechanism of formation by correlation of solid-state/solution structural information.
基金supported by National Natural Science Foundation of China(52302034,52402060,52202201,52021006)Beijing National Laboratory for Molecular Sciences(BNLMS-CXTD202001)+1 种基金Shenzhen Science and Technology Innovation Commission(KQTD20221101115627004)China Postdoctoral Science Foundation(2024T170972)。
文摘Graphdiyne(GDY)is a two-dimensional carbon allotrope with exceptional physical and chemical properties that is gaining increasing attention.However,its efficient and scalable synthesis remains a significant challenge.We present a microwave-assisted approach for its continuous,large-scale production which enables synthesis at a rate of 0.6 g/h,with a yield of up to 90%.The synthesized GDY nanosheets have an average diameter of 246 nm and a thickness of 4 nm.We used GDY as a stable coating for potassium(K)metal anodes(K@GDY),taking advantage of its unique molecular structure to provide favorable paths for K-ion transport.This modification significantly inhibited dendrite formation and improved the cycling stability of K metal batteries.Full-cells with perylene-3,4,9,10-tetracarboxylic dianhydride(PTCDA)cathodes showed the clear superiority of the K@GDY anodes over bare K anodes in terms of performance,stability,and cycle life.The K@GDY maintained a stable voltage plateau and gave an excellent capacity retention after 600 cycles with nearly 100%Coulombic efficiency.This work not only provides a scalable and efficient way for GDY synthesis but also opens new possibilities for its use in energy storage and other advanced technologies.
基金Technology Development Program of Jilin Province(YDZJ202201ZYTS640)the National Key Research and Development Program of China(2022YFB4200400)funded by MOST+4 种基金the National Natural Science Foundation of China(52172048 and 52103221)Shandong Provincial Natural Science Foundation(ZR2021QB024 and ZR2021ZD06)Guangdong Basic and Applied Basic Research Foundation(2023A1515012323,2023A1515010943,and 2024A1515010023)the Qingdao New Energy Shandong Laboratory open Project(QNESL OP 202309)the Fundamental Research Funds of Shandong University.
文摘Recently published in Joule,Feng Liu and colleagues from Shanghai Jiaotong University reported a record-breaking 20.8%power conversion efficiency in organic solar cells(OSCs)with an interpenetrating fibril network active layer morphology,featuring a bulk p-in structure and proper vertical segregation achieved through additive-assisted layer-by-layer deposition.This optimized hierarchical gradient fibrillar morphology and optical management synergistically facilitates exciton diffusion,reduces recombination losses,and enhances light capture capability.This approach not only offers a solution to achieving high-efficiency devices but also demonstrates the potential for commercial applications of OSCs.
基金financially supported by the National Key Research and Development Program of China(2023YFC3503902)the National Natural Science Foundation of China(82430108,82293681(82293680),and 82321004)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(2022B1515120015 and 2024A1515030103)the Guangdong Major Project of Basic and Applied Basic Research(2023B0303000026)the Science and Technology Projects in Guangzhou(202102070001)。
文摘Natural products,with their remarkable structural and biological diversity,have historically served as a vital bridge between chemistry,the life sciences,and medicine.They not only provide essential scaffolds for drug discovery but also inspire innovative strategies in drug development.The biomimetic synthesis of natural products employs principles from biomimicry,applying inspiration from biogenetic processes to design synthetic strategies that mimic biosynthetic processes.Biomimetic synthesis is a highly efficient approach in synthetic chemistry,as it addresses critical challenges in the synthesis of structurally complex natural products with significant biological and medicinal importance.It has gained widespread attention from researchers in chemistry,biology,pharmacy,and related fields,underscoring its interdisciplinary impact.In this perspective,we present recent advances and challenges in the biomimetic synthesis of natural products,along with the significance and prospects of this field,highlighting the transformative potential of biomimetic synthesis strategies for both chemical and biosynthetic approaches to natural product synthesis in the pursuit of novel therapeutic agents.
基金Joint Project of Dalian University of Technology-Dalian Institute of Chemical Physics (HX20230236)。
文摘Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive structure-directing agents(SDAs), pricey raw materials, and eco-unfriendly fluorine-containing additives. Here, we contributed a cost-effective and fluoride-free synthesis method for synthesizing high-quality MFI zeolite nanosheets through a Silicalite-1(Sil-1) seed suspension and urea cooperative strategy, only with inexpensive colloidal silica as the Si source. Our approach was effective for synthesizing both Sil-1 and aluminum-containing ZSM-5 nanosheets. By optimizing key synthesis parameters,including seed aging time, seed quantity, and urea concentration, we achieved precise control over the crystal face aspect ratio and b-axis thickness. We also revealed a non-classical oriented nanosheet growth mechanism, where Sil-1 seeds induced the formation of quasi-ordered precursor particles, and the(010)crystal planes of these particles facilitated urea adsorption, thereby promoting c-axis-oriented growth.The obtained ZSM-5 nanosheets exhibited exceptional catalytic performance in the benzene alkylation with ethanol, maintaining stability for over 500 h, which is 5 times longer than traditional ZSM-5 catalysts. Furthermore, large-scale production of ZSM-5 nanosheets was successfully carried out in a 3 L highpressure autoclave, yielding samples consistent with those from laboratory-scale synthesis. This work marks a significant step forward in the sustainable and efficient production of MFI nanosheets using inexpensive and environmentally friendly raw materials, offering the broad applicability in catalysis.
文摘Neurons are highly polarized cells with axons reaching over a meter long in adult humans.To survive and maintain their proper function,neurons depend on specific mechanisms that regulate spatiotemporal signaling and metabolic events,which need to be carried out at the right place,time,and intensity.Such mechanisms include axonal transport,local synthesis,and liquid-liquid phase separations.Alterations and malfunctions in these processes are correlated to neurodegenerative diseases such as amyotrophic lateral sclerosis(ALS).
基金supported by grants from the National Natural Science Foundation of China(grant number:32072756)Agricultural Research System of China(grant number:CARS-36).
文摘Background Milk synthesis is an energy-intensive process influenced by oxygen availability.This study investigates how hypoxia affects milk synthesis in BMECs,focusing on key genes involved in lactation and energy metabolism.Methods BMECs were cultured in a normoxic environment and then transferred to a hypoxia chamber with 1%O2 for specified durations.The study evaluated cellular responses through various molecular experiments and RNA sequencing.Small interfering RNA was employed to knock down HIF-1αto investigate whether the lactation-related phenotype alteration depends on HIF-1α.Results Hypoxia disrupted milk protein production by reducing mTOR/P70S6K/4EBP1 signaling and downregulating genes critical for amino acid transport and protein synthesis.Triglyceride synthesis increased due to enhanced fatty acid uptake and the upregulation of regulatory proteins,including FASN and PPARγ.Although glucose uptake was elevated under hypoxia,key enzymes for lactose synthesis were downregulated,suggesting a redirection of glucose toward energy production.Mitochondrial function was impaired under hypoxia,with reduced gene expression in TCA cycle,ETC,cytosol-mitochondrial transport,decreased ATP levels,increased ROS levels,and structural alterations.Additionally,lipid synthesis and glucose uptake depend on HIF-1α,while milk protein synthesis alterations occurred independently of HIF-1α.Conclusions Hypoxia alters milk synthesis in BMECs by disrupting milk protein synthesis,enhancing lipid metabolism,and impairing energy production.These findings provide valuable insights into the molecular mechanisms underlying the effect of oxygen deprivation on lactation efficiency,offering potential targets for mitigating hypoxic stress in the mammary glands of dairy animals.
基金supported by the Natural Science Foundation of Hebei Province(No.E2022208046)National Science Foundation of China(No.52004080)+2 种基金Key project of National Natural Science Foundation of China(No.U20A20130)Key research and development project of Hebei Province(No.22373704D)2023 Central Government Guide Local Science and Technology Development Fund Project(No.236Z1812 G)。
文摘Urbanization and industrialization have escalated water pollution,threatening ecosystems and human health.Water pollution not only degrades water quality but also poses long-term risks to human health through the food chain.The development of efficient wastewater detection and treatment methods is essential for mitigating this environmental hazard.Carbon dots(CDs),as emerging carbon-based nanomaterials,exhibit properties such as biocompatibility,photoluminescence(PL),water solubility,and strong adsorption,positioning them as promising candidates for environmental monitoring and management.Particularly in wastewater treatment,their optical and electron transfer properties make them ideal for pollutant detection and removal.Despite their potential,comprehensive reviews on CDs'role in wastewater treatment are scarce,often lacking detailed insights into their synthesis,PL mechanisms,and practical applications.This review systematically addresses the synthesis,PL mechanisms,and wastewater treatment applications of CDs,aiming to bridge existing research gaps.It begins with an overview of CDs structure and classification,essential for grasping their properties and uses.The paper then explores the pivotal PL mechanisms of CDs,crucial for their sensing capabilities.Next,comprehensive synthesis strategies are presented,encompassing both top-down and bottom-up strategies such as arc discharge,chemical oxidation,and hydrothermal/solvothermal synthesis.The diversity of these methods highlights the potential for tailored CDs production to suit specific environmental applications.Furthermore,the review systematically discusses the applications of CDs in wastewater treatment,including sensing,inorganic removal,and organic degradation.Finally,it delves into the research prospects and challenges of CDs,proposing future directions to enhance their role in wastewater treatment.
基金supported by the National Key Research and Development Program of China(2019YFA0905100)the National Natural Science Foundation of China(21991102,22378227).
文摘Constructing a framework carrier to stabilize protein conformation,induce high embedding efficiency,and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes.Hydrogen-bonded organic frameworks(HOFs)have promising application potential for embedding enzymes.In fact,no metal involvement is required,and HOFs exhibit superior biocompatibility,and free access to substrates in mesoporous channels.Herein,a facile in situ growth approach was proposed for the self-assembly of alcohol dehydrogenase encapsulated in HOF.The micron-scale bio-catalytic composite was rapidly synthesized under mild conditions(aqueous phase and ambient temperature)with a controllable embedding rate.The high crystallinity and periodic arrangement channels of HOF were preserved at a high enzyme encapsulation efficiency of 59%.This bio-composite improved the tolerance of the enzyme to the acid-base environment and retained 81%of its initial activity after five cycles of batch hydrogenation involving NADH coenzyme.Based on this controllably synthesized bio-catalytic material and a common lipase,we further developed a two-stage cascade microchemical system and achieved the continuous production of chiral hydroxybutyric acid(R-3-HBA).
基金supported by the Major Science and Technology Project of Zhongshan City(No.2022AJ004)the Key Basic and Applied Research Program of Guangdong Province(Nos.2019B030302010 and 2022B1515120082)Guangdong Science and Technology Innovation Project(No.2021TX06C111).
文摘In general,the rapid growth of α-Fe clusters is a challenge in high Fe-content Fe-based amorphous alloys,negatively affecting their physical properties.Herein,we introduce an efficient and rapid post-treatment technique known as ultrasonic vibration rapid processing(UVRP),which enables the formation of high-density strong magnetic α-Fe clusters,thereby enhancing the soft magnetic properties of Fe_(78)Si(13)B_(9) amorphous alloy ribbon.
文摘2-substituted-1-amino-o-carboranes 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10)(R=CH_(3),1a;R=Ph,1b)were synthesized and the reactions of these compounds with the yttrium dialkyl complex[Y(L)(CH_(2)SiMe3)_(2)](L=[2-(2,5-Me_(2)C_(4)H_(2)N)C_(6)H4NC(Ph)=NDipp]-,Dipp=2,6-iPr_(2)C_(6)H_(3))were investigated.The 1H NMR spectroscopy indicate that the reaction of ytrrium dialkyl complex with one equivalent of 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10) produce the mixture of ytrrium alkyl-amido complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))(CH_(2)SiMe3)](R=CH_(3),2a;R=Ph,2b)and bis(amido)complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))_(2)](R=CH_(3),3a;R=Ph,3b).The yttrium bridging imido complex[Y(L)(2-CH_(3)-1-N-o-C_(2)B_(10)H_(10))]_(2)(4a)was obtained by heating the mixture at 55℃for 12 h.Complex 3a was isolated and characterized by treating the yttrium dialkyl complex with two equivalents of 1a.The structures of complexes 3a and 4a were verified by single-crystal Xray diffraction.CCDC:2424136,3a;2424137,4a.
基金National Natural Science Foundation of China(22078125)Postdoctoral Science Foundation of China(2023M741472)Fundamental Research Funds for the Central Universities(JUSRP622038).
文摘Sunscreen agents derived from plants have been regarded as promising alternatives to artificial compounds.In this work,carbon dots(CDs)were prepared from carrot juice via a continuous microflowbased approach,where the influence of process parameters was studied and optimized.Complimentary characterization revealed the CDs not only have small size,narrow size distribution,and good water solubility,but also have abundant functional groups as well as excellent UV absorption performance.Relying on these properties,the CDs were used as UV absorbers,suggesting they have strong long-term UV absorption ability over a broad pH range.The UV-absorption properties of the CDs were confirmed by incorporating the CDs in polyvinyl alcohol(PVA)to get C-CDs@PVA films of different thickness,in which significantly enhanced UV absorption performance was observed.Besides,the sun protection performance is also related to the film thickness.Afterwards,the practical application of the CDs was evaluated by adding them in a typical skin cream.With the addition of the CDs,the cream has drastically reduced UV transmittance in both UVA and UVB regions,and exhibits better UV absorption performance than commercial sunscreen agents.The CDs also demonstrated low cytotoxicity and high DPPH radical scavenging activity,making them promising as green sunscreen absorbers.This work is expected to provide a guidance for the development of green and effective natural sunscreen agents via microflowbased method.
文摘Fischer-Tropsch synthesis(FTS)and hydroformylation are pivotal chemical processes for converting syngas and olefins into valuable hydrocarbons and chemicals.Recent advancements in catalyst design,reaction mechanisms,and process optimization have significantly improved the efficiency,selectivity,and sustainability of these processes.This Account introduces the relevant research activities in the Research Center for Catalysis in Syngas Conversion and Fine Chemicals(DNL0805)of Dalian Institute of Chemical Physics(DICP),Chinese Academy of Sciences.The reactions of interests include FTS,heterogeneous hydroformylation of olefins,alcohol dehydration and oxidation,andα-olefin polymerization,with the emphasis on developing innovative catalysts and processes to address the challenges of traditional processes.Exemplified by the discovery of robust Co-Co_(2)C/AC for FTS and Rh_(1)/POPs-PPh_(3) for heterogeneous hydroformylation of olefins,it demonstrates how lab-scale fundamental understandings on the active sites of catalysts leads to pilot-plant scale-up and finally commercial technologies.Perspectives on the challenges and directions for future developments in these exciting fields are provided.
文摘Continuous research on Cephalotaxus plants has ultimately led to the US food and drug administration (FDA) ap-provalof homoharringtonine in 2012 for the treatment of chronic myeloid leukemia. Additionally, another important class of natural products from Cephalotaxus plants is cephalotane diterpenoids. Since the discovery of the first member, harring-tonolide,in 1978, cephalotane diterpenoids have garnered significant attention from the scientific community due to their re-markableanti-cancer activity. The unique structural features of cephalotane diterpenoids, a 7/6/5/6-fused tetracyclic carbon skeleton and a bridged lactone, make them ideal targets for synthetic chemists. Successfully synthesizing these complex diterpenoids is of great importance for the discovery and development of anti-tumor drugs. To date, ten research groups have completed the total synthesis of 24 cephalotane diterpenoids. The latest progress in the total synthesis of cephalotane diterpe-noidsis reviewed, showcasing the importance of these innovative synthetic strategies in the efficient synthesis of complex natural products and their potential significance in advancing the field of drug discovery.
基金National Natural Science Foundation of China(Grant No.22005275)to provide fund for conducting experiments.
文摘In order to improve the energy output consistency of 3, 3’-diamino-4, 4’-azoxyfurazan(DAAF) in the new insensitive booster and the safety and efficiency in the preparation process, a continuous preparation system of DAAF from synthesis to spherical coating was designed and established in this paper, which combined ultrasonic micromixing reaction with microdroplet globular template. In the rapid micromixing stage, the microfluidic mixing technology with ultrasonic was used to synergistically strengthen the uniform and rapid mass transfer mixing reaction between raw materials to ensure the uniformity of DAAF particle nucleation-growth, and to prepare high-quality DAAF crystals with uniform structure and morphology and concentrated particle size distribution. In the microdroplet globular template stage, the microfluidic droplet technology was used to form a droplet globular template with uniform size under the shear action of the continuous phase of the dispersed phase solution containing DAAF particles and binder. The size of the droplet template was controlled by adjusting the flow rate ratio between the continuous phase and the dispersed phase. In the droplet globular template, with the diffusion of the solvent in the dispersed phase droplets, the binder precipitates to coat the DAAF into a ball, forming a DAAF microsphere with high sphericity, narrow particle size distribution and good monodispersity. The problem of discontinuity and DAAF particle suspension in the process was solved, and the coating theory under this process was studied. DAAF was coated with different binder formulations of fluororubber(F2604), nitrocellulose(NC) and NC/glycidyl azide polymer(GAP), and the process verification and evaluation of the system were carried out. The balling effects of large, medium and small droplet templates under different binder formulations were studied. The scanning electron microscope(SEM) results show that the three droplet templates under the three binder formulations exhibit good balling effect and narrow particle size distribution. The DAAF microspheres were characterized by powder X-ray diffraction(XRD), differential scanning calorimetry(DSC), thermo-gravimetric(TG) and sensitivity analyzer. The results showed that the crystal structure of DAAF did not change during the process, and the prepared DAAF microspheres had lower decomposition temperature and lower mechanical sensitivity than raw DAAF. The results of detonation parameters show that the coating of DAAF by using the above three binder formulations will not greatly reduce the energy output of DAAF, and has comparable detonation performance to raw DAAF. This study proves an efficient and safe continuous system from synthesis to spherical coating modification of explosives, which provides a new way for the continuous, safe and efficient preparation of spherical explosives.
基金National Key Research and Development Program of China(2022YFB3708500,2023YFB3611000)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2020ZZ109)。
文摘Currently,the carbothermal reduction-nitridation(CRN)process is the predominant method for preparing aluminum nitride(AlN)powder.Although AlN powder prepared by CRN process exhibits high purity and excellent sintering activity,it also presents challenges such as the necessity for high reaction temperatures and difficulties in achieving uniform mixing of its raw materials.This study presents a comprehensive investigation into preparation process of AlN nanopowders using a combination of hydrothermal synthesis and CRN.In the hydrothermal reaction,a homogeneous composite precursor consisting of carbon and boehmite(γ-AlOOH)is synthesized at 200℃using aluminum nitrate as the aluminum source,sucrose as the carbon source,and urea as the precipitant.During the hydrothermal process,the precursor develops a core-shell structure,with boehmite tightly coated with carbon(γ-AlOOH@C)due to electrostatic attraction.Compared with conventional precursor,the hydrothermal hybrid offers many advantages,such as ultrafine particles,uniform particle size distribution,good dispersion,high reactivity,and environmental friendliness.The carbon shell enhances thermodynamic stability of γ-Al_(2)O_(3) compared to the corundum phase(α-Al_(2)O_(3))by preventing the loss of the surface area in alumina.This stability enables γ-Al_(2)O_(3) to maintain high reactivity during CRN process,which initiates at 1300℃,and concludes at 1400℃.The underlying mechanisms are substantiated through experiments and thermodynamic calculations.This research provides a robust theoretical and experimental foundation for the hydrothermal combined carbothermal preparation of non-oxide ceramic nanopowders.
文摘A strategy for the green synthesis of heterocyclicβ-ketosulfides via nucleophilic substitution ofα-halogenated ketone with het-eroaryl thiols in water media is presented.Compared with the available literature reports,this new method had the advantages of base-free,additives-free,simple operation,mild condition,greenness,high efficiency,tolerance of a broad scope of substrates.Furth-more,the reaction could easily be scaled up in gram scale and the products also could easily transformed to other useful organic compounds.Mechanism investigation indicated that the tautomerism of pyrimidine-2-thiol to pyrimidine-2(1H)-thione and the hy-drogen bonds played important roles in the reaction.
文摘The rapid integration of Internet of Things(IoT)technologies is reshaping the global energy landscape by deploying smart meters that enable high-resolution consumption monitoring,two-way communication,and advanced metering infrastructure services.However,this digital transformation also exposes power system to evolving threats,ranging from cyber intrusions and electricity theft to device malfunctions,and the unpredictable nature of these anomalies,coupled with the scarcity of labeled fault data,makes realtime detection exceptionally challenging.To address these difficulties,a real-time decision support framework is presented for smart meter anomality detection that leverages rolling time windows and two self-supervised contrastive learning modules.The first module synthesizes diverse negative samples to overcome the lack of labeled anomalies,while the second captures intrinsic temporal patterns for enhanced contextual discrimination.The end-to-end framework continuously updates its model with rolling updated meter data to deliver timely identification of emerging abnormal behaviors in evolving grids.Extensive evaluations on eight publicly available smart meter datasets over seven diverse abnormal patterns testing demonstrate the effectiveness of the proposed full framework,achieving average recall and F1 score of more than 0.85.
基金supported in part by National Natural Science Foundation of China under Grant No.62473013Key Project of Science and Technology Innovation and Entrepreneurship of TDTEC(No.2022-TDZD004).
文摘The newly emerging neural radiance fields(NeRF)methods can implicitly fulfill three-dimensional(3D)reconstruction via training a neural network to render novel-view images of a given scene with given posed images.The Instant Neural Graphics Primitives(Instant-NGP)method further improves the position encoding of NeRF.It obtains state-of-the-art efficiency.However,only a local pixel-wised loss is considered when training the Instant-NGP while overlooking the nonlocal structural information between pixels.Despite a good quantitative result,it leads to a poor visual effect,especially the completeness.Inspired by the stochastic structural similarity(S3IM)method that exploits nonlocal structural information of groups of pixels,this paper proposes a new method to improve the completeness of fast novel view synthesis.The proposed method first extends the thread-wised processing of the Instant-NGP to the processing in a customthread block(i.e.,a group of threads).Then,the relative dimensionless global error in synthesis,i.e.,Erreur Relative Globale Adimensionnelle de Synthese(ERGAS),of a group of pixels corresponding to a group of threads is computed and incorporated into the loss function.Extensive experiments validate the proposed method.It can obtain better quantitative results than the original Instant-NGP with fewer iteration steps.PSNR is increased by 1%.Amazing qualitative results are obtained,especially for delicate structures and details such as lines and continuous structures.With the dramatic improvements in the visual effects,our method can boost the practicability of implicit 3D reconstruction in applications such as self-driving and augmented reality.
